To export the delivery logs, you can go to the specific delivery dashboard and then delivery logs (3 dots on bottom right corner). Under the Sending Logs, click on the download icon to export these logs into a comma separated txt file
This will not have the content message content/ mirror page url in it which you can get by clicking on the "Edit Properties" of the specific message in the Sending Logs.
Mirror page URL is generated for each email sent out. It cannot be retrieved before it is sent out and cannot be accessed in a workflow.